The Boston Celtics rookies are getting nicknames, compliments of the man himself known as “KG” and “The Big Ticket.” Garnett went out of his way on Friday to make it clear that he’s doing it to be affectionate and not because, like many veterans throughout basketball and other sports, he can’t be troubled to learn their real names.

“My personal connection is a nickname. I’m not disrespecting people by not knowing their names,” Garnett said. “Some people don’t even talk to rookies.”

The Celtics are still loaded with aging veterans, relying heavily on Garnett and Paul Pierce along with new additions Jason Terry and Jason Collins. But the leadership in the process of passing to 26-year-old point guard Rajon Rondo, and this year’s crop of rookies could be the most productive since 2004, when Doc Rivers was himself in his first year with the team.

Sullinger and Melo were first-round draft picks, with Kris Joseph coming in the second round. (Garnett calls Joseph “Shawn,” Christmas said, “because he reminds him of someone named Shawn.”)

“Most of the time, it’s just ‘Young’un,’” Sullinger said. “Knowing that he’s an NBA dinosaur, you’ve got to understand that being a ‘young’un’ is a good thing.”

Christmas was a 2009 draft choice of the Philadelphia 76ers who played in Europe the past three seasons and would be happy to be called anything by Garnett or any of the Celtics once the final roster cuts are made. “For him to recognize me, for him to put an interest in me as a teammate, it’s definitely humbling,” Christmas said.

Sullinger is also enjoying his time with his new mentor. Garnett has been running a sort of big-man camp within training camp, coach Doc Rivers said, and the 2004 NBA MVP has been passing along what he knows to Sullinger and Collins as well as returnees Chris Wilcox and Brandon Bass.

“I’m a big fan of veterans ... teaching some of the young guys on work ethics, earning what you get, not just riding off potential,” Garnett said. “I’ve always been a big fan of veterans” doing that.

The Celtics returned this week from exhibitions in Milan and Istanbul and will meet the New York Knicks on Saturday night in Hartford, Conn. — their first practice game against NBA opponents.

Sullinger is trying to soak it all up.

“Being a rookie, you always have to pay homage to the veterans,” he said. “You come in, you’ve got to have a closed mouth and you play basketball.”